<!DOCTYPE html>
<html>
<body>
<p>You can delete object properties.</p>
<p id="demo"></p>
<script>
var person = {
firstname:"John",
lastname:"Doe",
age:50,
eyecolor:"blue"
};
delete person.age;
document.getElementById("demo").innerHTML =
person.firstname + " is " + person.age + " years old.";
</script>
</body>
</html>